Unit 1 Section 2 Easy

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Questions and Answers

How does a flagellum behave when there is no chemical attractant present?

Spiral movement toward stimuli

Consistent linear movement

Frequent tumbling due to lack of orientation (correct)

Increased running with direction

Which type of bacteria possess endoflagella?

Mycoplasma

Cocci

Spirochetes (correct)

Bacilli

What is the primary function of fimbrae in bacteria?

Energy production

Genetic material transfer

Attachment to surfaces (correct)

Protection against phagocytosis

What role does the bacterial cell wall play?

Maintains shape and prevents bursting Signup and view all the answers

Which component is a key polysaccharide in bacterial cell walls?

Peptidoglycan Signup and view all the answers

What distinguishes Gram positive bacteria from Gram negative bacteria?

Presence of a thick peptidoglycan layer Signup and view all the answers

What is lipid A classified as in Gram-negative bacteria?

Endotoxin Signup and view all the answers

How do porins contribute to the virulence of Gram negative bacteria?

Prevent antibiotic entry Signup and view all the answers

What unique characteristic does Mycoplasma bacteria exhibit?

Absence of a cell wall Signup and view all the answers

Which statement best describes the fluid mosaic model of the cell membrane?

A dynamic arrangement of lipids and proteins Signup and view all the answers

Which structures are shared by both eukaryotes and prokaryotes?

Ribosomes Signup and view all the answers

What is the typical form of reproduction in bacteria?

Binary fission Signup and view all the answers

How do prokaryotic and eukaryotic DNA differ in structure?

Eukaryotes have linear DNA Signup and view all the answers

What best describes pleomorphic bacteria?

Bacteria that vary in size and shape Signup and view all the answers

What is the primary function of the glycocalyx in bacteria?

Trapping nutrients and evading host defenses Signup and view all the answers

Which arrangement of flagella consists of one flagellum at one end of the bacterium?

Monotrichous Signup and view all the answers

What distinguishes the structure of Gram positive flagella from Gram negative flagella?

Gram positive flagella have one set of rings and a thick peptidoglycan layer Signup and view all the answers

What describes the difference between cytoplasm and cytosol?

Cytoplasm includes all cell structures and fluid, cytosol is just the fluid Signup and view all the answers

Which statement correctly describes bacterial flagella?

They rotate to propel the cell Signup and view all the answers

What is the defining characteristic of a capsule form of glycocalyx?

Well organized and tightly attached Signup and view all the answers

What is the primary role of enzymes in chemical reactions?

They decrease activation energy. Signup and view all the answers

What is a coenzyme?

It is an organic cofactor derived from vitamins. Signup and view all the answers

Where does substrate binding occur in an enzyme?

Active site Signup and view all the answers

What distinguishes competitive inhibition from non-competitive inhibition?

It competes for the active site. Signup and view all the answers

Which process results in the conversion of glucose into pyruvate?

Glycolysis Signup and view all the answers

What characterizes the energy investment phase of glycolysis?

Use of ATP to phosphorylate glucose. Signup and view all the answers

How does aerobic respiration differ from anaerobic respiration?

It uses oxygen as the final electron acceptor. Signup and view all the answers

What is the outcome of feedback inhibition in metabolic pathways?

It inhibits an enzyme by the end product. Signup and view all the answers

What happens during the energy payoff phase of glycolysis?

4 ATP, 2 NADH, and 2 pyruvate are generated. Signup and view all the answers

What is a defining feature of anaerobic fermentation?

It occurs without oxygen and does not require an electron transport chain. Signup and view all the answers

Study Notes

Shared Structures of Eukaryotes and Prokaryotes

Common structures: plasma membrane, cytoplasm, ribosomes, and DNA.

Unique Structures in Prokaryotes

Contains circular DNA, cell membrane, cytoplasm, and bacterial flagella.

Unique Structures in Eukaryotes

Comprises linear DNA, plasma membrane, endomembrane system, mitochondria, chloroplasts, flagella, and cilia.

DNA Storage

Prokaryotic DNA: stored in a singular circular chromosome located in the nucleoid.
Eukaryotic DNA: stored in multiple linear chromosomes within the nucleus.

Cytoplasm vs. Cytosol

Cytoplasm includes all cell structures and fluid.
Cytosol refers specifically to the fluid component.

Flagella Differences

Prokaryotic flagella are simpler, rotating to propel the cell.
Eukaryotic flagella exhibit a complex, whip-like motion.

Bacterial Reproduction

Bacteria primarily reproduce by binary fission, resulting in two daughter cells.

Pleomorphic Bacteria

Pleomorphic bacteria can vary in size and shape.

Bacterial Arrangements

Diplo: pairs
Strepto: chains
Staphylo: clusters
Tetrads: groups of four

Glycocalyx

A gelatinous layer surrounding some bacterial cells, aiding in protection and attachment.

Forms of Glycocalyx

Capsule: well-organized, tightly attached.
Slime Layer: less organized, loosely attached.

Glycocalyx Functions

Traps nutrients, aids in surface attachment, and helps evade host immune responses.

Flagellum Function

Provides mobility, allowing bacteria to respond to environmental stimuli.

Flagella Arrangements

Monotrichous: single flagellum.
Amphitrichous: one or more flagella at each end.
Lophotrichous: cluster of flagella at one end.
Peritrichous: flagella distributed around the cell.

Flagellum Components

Filament: outer region extending from the cell.
Hook: connects the filament to the cell surface.
Basal body: anchors the flagellum to the cell wall and plasma membrane.

Gram Positive vs. Gram Negative Flagella

Gram Positive: has one set of rings, a single membrane, and a thick peptidoglycan layer.
Gram Negative: contains two sets of rings, two membranes (outer and inner), and a thin peptidoglycan layer.

Flagellum Movement

Movement generated by changing flagellar rotation; straight runs occur with stimuli, and more tumbling happens without stimuli.

Endoflagella

Found in spirochetes, providing unique movement capabilities.

Fimbriae Function

Hair-like structures used for attachment to specific surfaces.

Pilus Function

Facilitates bacterial conjugation, transferring genetic material between bacteria.

Cell Wall Function

Maintains bacterial shape and prevents lysis.

Bacterial Cell Wall Composition

Contains peptidoglycans made up of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM), along with tetrapeptides.

Gram Positive vs. Gram Negative Cell Walls

Gram Positive: thick peptidoglycan layer with teichoic acids.
Gram Negative: thin peptidoglycan layer, outer membrane containing lipopolysaccharides (LPS).

Lipopolysaccharides (LPS)

Macromolecules found in Gram negative outer membranes, serving as virulent factors and triggering strong immune responses.

Mycoplasma Bacteria

Lack a cell wall, making them unique among bacteria.

Fluid Mosaic Model

Describes the cell membrane as a dynamic structure composed of a phospholipid bilayer with proteins that move fluidly.

Phospholipids

Contain hydrophilic phosphate heads and hydrophobic fatty acid tails, creating a bilayer.

Endospores

Highly resistant, dormant structures formed by bacteria under harsh environmental conditions.

Metabolism Overview

Metabolism encompasses all chemical reactions maintaining life, with energy stored as ATP.

Catabolic vs. Anabolic Reactions

Catabolic reactions break down large molecules, releasing energy.
Anabolic reactions synthesize larger molecules from smaller ones, consuming energy.

Enzymes

Catalysts that speed up reactions by binding substrates to active sites; can have cofactors (inorganic) and coenzymes (organic, derived from vitamins).

Active vs. Allosteric Sites

Active site: where substrate binds.
Allosteric site: alternative binding site that can affect enzyme activity.

Pathway Modulation Mechanisms

Competitive inhibition: substrate competes for the active site.
Non-competitive inhibition: alters enzyme shape, preventing substrate binding.
Feedback inhibition: end products inhibit an upstream enzyme.

Glycolysis Overview

Breaks down glucose into 2 pyruvate, divided into an energy investment phase (uses 2 ATP) and an energy payoff phase (produces 4 ATP, 2 NADH, and 2 pyruvate).

Glucose Catabolism Pathways

Aerobic respiration: uses oxygen as the final electron acceptor.
Anaerobic respiration: does not use oxygen but employs an alternative electron acceptor.
Anaerobic fermentation: occurs without oxygen or electron transport chain participation.

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Description

Explore the fundamental structures shared between prokaryotes and eukaryotes in this quiz. Learn about the unique cellular components of each organism, including their DNA storage differences. Test your knowledge on the essentials of cell biology!